VR: Heat Affecting Dashpot?

[milepost]

Sorry that post included my post, within the quote! Soulbear... I'm in contact with Airpot at the moment, will be upgrading for sure Glad to see good reports from it!

I'm super interested in this! I have more than 1 t560 and am totally up for experimenting. Comparing the ones I have for many years, they behave differently for sure.

Let us know which airport you get!

Cheers

[PMST]

Will do, talking to them now, just sending them full info and they are advising what is best.... soon as i get info i'll post it here

[milepost]

Awesome, I will definitely sacrifice a T560 to test out some new stuff and share it.

[milepost]

Will do, talking to them now, just sending them full info and they are advising what is best.... soon as i get info i'll post it here

Yo hi! Did Airpot get back to you? Cheers.

[discosdecorte]

Hi Trolls,
[...]
Examples of Modifications Demonstrating such changes are possible :-

Airpot on Hara M180 Lathe.jpg


Airpot on BSR DR33C Lathe.jpg

Airpot on Presto-Sugden Adaptor-1.jpg

Hi!

Yep, I am the guy with the Airpot mounted in a small Hara M180 lathe. I've started worrying about adding a dashpot system when Steven from MyShank asked me if I was using one when I ruined my first diamond stylus after 30 blanks only. After reading some posts about it I found this:
https://www.lathetrolls.com/viewtopic.php?t=6852
So I asked Soulbear and he told me about the only-push Airpot he hacked to get a fully functional push/pull Airpot. And he is such a generous guy! The Bear himself sent me a Airpot and helped me LOTS to figure out how to mount it in a tiny lathe like mine (so thanks again, Soulbear. You are the best!)

Do I need a dashpot/airpot system in such a tiny lathe? I am not sure. Will It harm? I don't think so. The only thing I know for sure is that I've cut like 80 blanks since I have it on my Hara lathe and the cutting stylus is alive and fully functional You can see a small video in my IG account: https://www.instagram.com/p/CCtclqenw2C/?igshid=1gjl9x8b982rv

Best regards,
Fer

[Soulbear]

Yep, I am the guy with the Airpot mounted in a small Hara M180 lathe. I've started worrying about adding a dashpot system when Steven from MyShank asked me if I was using one when I ruined my first diamond stylus after 30 blanks only. After reading some posts about it I found this:
https://www.lathetrolls.com/viewtopic.php?t=6852
So I asked Soulbear and he told me about the only-push Airpot he hacked to get a fully functional push/pull Airpot. And he is such a generous guy! The Bear himself sent me a Airpot and helped me LOTS to figure out how to mount it in a tiny lathe like mine (so thanks again, Soulbear. You are the best!)

Do I need a dashpot/airpot system in such a tiny lathe? I am not sure. Will It harm? I don't think so. The only thing I know for sure is that I've cut like 80 blanks since I have it on my Hara lathe and the cutting stylus is alive and fully functional You can see a small video in my IG account: https://www.instagram.com/p/CCtclqenw2C/?igshid=1gjl9x8b982rv

Thank You for your kind words Fer, yes Hacking a Airpot indeed. Some time ago I was hunting around for alternatives to the extraordinarily "Expensive" Push-Pull Dashpot I bought from here :- http://www.springfixlinkages.com/en/catalog/air-cylinders/dashpots/push-pull-dampers/l4570

When the carriage from the USA was added in, and the 20% Tax was included, this was not an inconsiderable sum to pay out!!! This particular Dashpot was the thick-end of £100 and is now fitted on the BSR DR33C Lazarus Lathe Project

BSR DR33C Restoration-62.jpg

I came upon a Job-Lot on the Bay, of what were onerously described as "Airpot Dashpots" After waiting an eternity for the seller to get them to me, I found only one of the Dashpots was actually a Dashpot!! That is to say, a "Double-acting, Bi-directional, Damper" The rest of the items are what are termed "Snubbers" and only restrict the Piston Motion in a single direction!!

Taking one of the "Snubbers" apart I found the thing to have a Rubber Diaphragm attached to the Crown of the Graphite Piston, this concealed a Small Bore Port to allow Air into the Cylinder as can be seen here :-
.

Snubber Diaphragm-1.jpg

This diaphragm is in effect, the "ONE WAY" Valve which makes the difference between a "Dashpot and a Snubber" Pulling back the Diaphragm reveals the Port which allows Air INTO the Cylinder as the Pistom is Descending, therefore offering no resistance to the Movement of the Piston. When the Piston is Ascending, the Diaphragm seals the Port and the Piston is offered resistance to motion. The simple expedient of sealing the Port with "Clear Lacquer/Nail Polish" converts the Snubber into a Dashpot Propper.

So fellow LatheTrolls, I hope you found this useful, and if ever you happen upon a Job-Lot of Snubbers, but are Looking for a Dashpot, Grab some of these!!

Best Regards Soulbear

[PMST]

This is all great info, thanks!

I am talking to Airpot at the moment, I have gone into details about what is needed and they recommend a '2K59' with modified rod lengths, I will keep you all posted with how I get on too

[Naboo]

A bit late to the party here.... but I'm currently building an oil/spring dashpot, and working on a suspension design.

But am interested to know.. when pulling the head lever down, does the lever just add a small amount of weight causing the head to drop ?
or is there some sort of mechanism going on ? like a lobe hidden inside that controls the drop ?

Hoping to make something similar, or improve on it

Cheers

[Discomo]

deleted

[Discomo]

Hi Trolls,
Forgive me for “Chipping In” here, and please understand I am not Criticising anyone by any means!! I am not, nor after now waiting for over 4 years for a response from Herr “S” am I ever likely to be, a VR Owner. But this has not stopped me following this thread with Great Interest, sometimes with Amusement, and sometimes with Bafflement!!. It seems to me that VR Owners are “Quite Reluctant” to Change Very Much about the Design of their VR Lathes in case they somehow “Break” what they perceive to be “the Magic Spell” that makes the VR what it is. This behaviour strikes me as somewhat “Odd in the Extreme” and this makes me curious.
Not all designs are “Perfect” from the “Get GO” and they are of their Own Time, and could maybe stand to be sympathetically modernised and improved upon over time??

Take this for a simple example

“Writing!!” :-

At first Rocks and Stones were used to scrape marks on trees and cave walls, This progressed to dipping the Pointed Tips of Feathers of some Dead Bird into some blood, and scratching marks on animal skins, then along comes the Egyptians with Papyrus, and the Chinese with paper, then we discovered inks, and metalworking for pen nibs, moved onto desks, with pencils, inkwells, fountain pens, biro’s, felt tips, word processors, computers, the works etc etc. All progression over time?? In this modern world this “Speed of Development” has increased exponentially, not in all areas, but many nonetheless. What formerly took many years to design on a Drawing Board, then to develop Prototypes, then Gear Up for Mass Production, can now be done at home on a PC with a Plastic or Metal Printer by a reasonably Savvy Child, in a FEW HOURS!! I read somewhere that if the Automobile Industry had kept pace with the Electronics/Computer Industry, we would now be able to make a Car Journey the equivalent of to the Moon and Back to Earth, on one Tank of Gas!!


If a design has Obvious Drawbacks or Flaws, then WHY NOT CHANGE IT??
Whilst I can appreciate that there may be very many various “Factors” at Play” as to why this may be so, thereby Validating a VR owners decision not change things because of “Time Constraints, Fear of Destroying the Value of the VR, Fear of Potentially Damaging the VR, Loss of Income/Livelihood” etc etc….! I do not think it conceivable, that this applies in each and every VR Owners case. The VR has been around since 2009-ish, so at a conservative 1 or 2 sales a month, that would mean that would maybe mean there are maybe a couple of hundred VR’s now in use Worldwide??? I have also heard muted the possibility of going the “Air Pot/Damper” Route, this also strikes me as being “Worth a Shot” I know at least one of my Lathtroll Buddies is modifying his VR to “Airpot Damping” as I write, and I will encourage him to Post the results of his endeavours here on the Forum , but out of the many Lathetrolls who own the VR, why not others??? Gravity can sometimes be a bit of a nuisance. Oil is Messy!! Oil (Usually) Flows Downhill, therefore the “VR Dashpot” also therefore needs to be as Close to Vertical as Practicable. Do other Lathetrolls not share my view that this is a “Design Limitation” restricting Optimum Positioning on the VR??? One that would not exist if the “Airpot Alternative” was used instead???
Examples of Modifications Demonstrating such changes are possible :-


My point is this, Why to bother your heads with unnecessary formulae, Temperature Coefficients,, or worry about finding the correct “Weight/Viscosity” of Oil??
Simply Modify the VR And at a Cost of $1 per 1000 Spring/Units, Choose maybe a few "Different Springs" to Try Out, Fit an “Airpot” and Adjust 1 Screw to tune the System!!! And Let us know the results
Regards Soulbear

Hey Soulbear

For some reason I totally missed your post.

Great idea’s
Especially the part with the “ Pointed Tips of Feathers of some Dead Bird”

And also about the airpot idea

Thing is, the technical (building) part is by far not my strongest point. My qualities ly in mastering and cutting. But things like problem solving on the technical side it’s not my thing. Then again, as a cutter you almost need to have certain building skills. But for me it would be so much more convenient when it would simply be a matter of changing a part and that it will instantly work without having to be an engineer.

[Naboo]

Iv'e seen a lot of talk about those airpots, but haven't heard they work well.
due to using air, there is a tiny delay in the pressure building up before it actually functions.
So presumably... (as I haven't used one) I'm guessing you'd either have a dead spot of not enough damping, or you'd have to over compensate and make it set too hard ?

Anyway, I see oil as being more consistent so am building one similar to the VR's but with room to modify it still if it can be made better.

I'm building a full lathe from scratch based around a Technics SP-15...
but I just can't for the life of me figure out a drop lever design that's somewhat floating so will allow the dashpot to work properly, if anyone has some advise/examples please ??

[Dogtemple]

but I just can't for the life of me figure out a drop lever design that's somewhat floating so will allow the dashpot to work properly, if anyone has some advise/examples please ??

couldn't you just make it rise on a cam, so it only touches when lifting and not touching the rest of the time?

[Dogtemple]

please forgive the crudeness of my illustration

pivot cam.jpg

[boryo]

A bit late to the party here.... but I'm currently building an oil/spring dashpot, and working on a suspension design.

But am interested to know.. when pulling the head lever down, does the lever just add a small amount of weight causing the head to drop ?
or is there some sort of mechanism going on ? like a lobe hidden inside that controls the drop ?

Hoping to make something similar, or improve on it

Cheers

You can take a look of this Presto 75A: https://drive.google.com/drive/folders/1114kxllyPk7WETrqsAA7vksJkEdBrnO1
Look carefully the photo with the head and 'suspension'. There is another photo of a drawing that I've tried to make for you. Basically, there is a shaft that the head lies on it and half of it is removed under the head suspension/connection (the part that head is connected to the arm). So when you move the lever, the shaft turns and since the head 'part' lies on. the shaft it goes down slowly because the shaft is cut on half. I'm sorry for my poor explanation, take a look and let me know if you need some more clarifications

[Naboo]

aha ! makes perfect sense..

Thanks Dogtemple & boryo